Apparatus and method for estimating direction of sound by using acoustic sensor

ABSTRACT

Provided is a direction estimating apparatus using an acoustic sensor, the direction estimating apparatus including a non-directional acoustic sensor, a plurality of directional acoustic sensors provided adjacent to the non-directional acoustic sensor, and a processor configured to obtain a first output signal from the non-directional acoustic sensor and a plurality of second output signals from the plurality of directional acoustic sensors, and estimate a direction of a sound source within an error range from -5 degrees to +5 degrees by comparing magnitudes between the two output signals and phase information between the first output signal and one of the second output signals.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Korean Patent Application No.10-2021-0183130, filed on Dec. 20, 2021, in the Korean IntellectualProperty Office, the disclosure of which is incorporated by referenceherein in its entirety.

BACKGROUND 1. Field

Example embodiments of the present disclosure relate to apparatuses andmethods for estimating a direction by using an acoustic sensor.

2. Description of Related Art

Acoustic sensors, which are mounted in household appliances, imagedisplay devices, virtual reality devices, augmented reality devices,artificial intelligence speakers, and the like to detect a directionfrom which sounds are coming and recognize voices, are used inincreasingly more areas. Recently, a directional acoustic sensor thatdetects sound by converting a mechanical movement due to a pressuredifference, into an electrical signal has been developed.

SUMMARY

One or more example embodiments provide apparatuses and methods forestimating a direction by using an acoustic sensor. The technicalobjective to be achieved by the present embodiment is not limited to theabove technical objectives, and other technical objectives may beinferred from the example embodiments below.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice example embodiments of the disclosure.

According to an aspect of an example embodiment, there is provided adirection estimating apparatus using an acoustic sensor, the directionestimating apparatus including a non-directional acoustic sensor, aplurality of directional acoustic sensors provided adjacent to thenon-directional acoustic sensor, and a processor configured to obtain afirst output signal from the non-directional acoustic sensor and aplurality of second output signals from the plurality of directionalacoustic sensors, and estimate a direction of a sound source within anerror range from -5 degrees to +5 degrees by comparing magnitudesbetween the two output signals and phase information between the firstoutput signal and one of the second output signals.

The plurality of directional acoustic sensors may include threedirectional acoustic sensors provided in a triangular shape or radialshape with respect to the non-directional acoustic sensor.

The processor may be further configured to exclude a second outputsignal having a smallest magnitude from among the second output signals,and estimate the direction of the sound source based on phaseinformation of an output signal obtained by adding the first outputsignal and the other second output signals.

The processor is further configured to select a second output signalhaving a greatest magnitude when the other second output signals areplural, and estimate the direction of the sound source based on phaseinformation of the output signal obtained by adding the first outputsignal and the selected second output signal.

The processor may be further configured to compare whether phaseinformation between the first output signal and one of the second outputsignals is greater than 0.

The direction of the sound source may be differently estimated based ona number of the plurality of directional acoustic sensors andarrangement of the plurality of directional acoustic sensors.

A directional shape of the second output signals may include afigure-of-8 shape regardless of a frequency of the sound source.

The processor may be further configured to obtain, when the plurality ofdirectional acoustic sensors are three, the direction of the soundsource according to

$\theta = {\sum\limits_{i = 0}^{3}{c_{i} \cdot r^{i}}}\,\text{,}$

where Ci is an arbitrary coefficient, and ri is a power factor.

The processor may be further configured to compare, when there are twodirectional acoustic sensors, whether phase information of the outputsignal obtained by adding a second output signal having a greatermagnitude among the two second output signals and the first outputsignal of the non-directional acoustic sensor is greater than 0.

The processor may be further configured to obtain the direction of thesound source according to

$\theta = cos^{- 1}\frac{P_{1}}{\sqrt{\left( P_{1} \right)^{2} + \left( P_{2} \right)^{2}}}\mspace{6mu},$

where, P1 is greatest power, and P2 is smallest power.

The two directional acoustic sensors may be provided to be perpendicularto each other.

The processor may be further configured such that, when the plurality ofdirectional acoustic sensors are four, each two directional acousticsensors are provided to face each other.

The processor may be further configured to determine a directionalacoustic sensor corresponding to a second output signal having agreatest magnitude among the plurality of second output signals, andcompare a magnitude of the determined directional acoustic sensor withmagnitudes of second output signals of two adjacent directional acousticsensors provided on a left side and a right side.

The non-directional acoustic sensor and the plurality of directionalacoustic sensors may be provided within a diameter of 3 cm.

According to another aspect of an example embodiment, there is providedan electronic device including a direction estimating apparatus using anacoustic sensor including a non-directional acoustic sensor, a pluralityof directional acoustic sensors provided adjacent to the non-directionalacoustic sensor, and a processor configured to obtain a first outputsignal from the non-directional acoustic sensor and a plurality ofsecond output signals from the plurality of directional acousticsensors, and estimate a direction of a sound source within an errorrange from -5 degrees to +5 degrees by comparing magnitudes between thetwo output signals and phase information between the first output signaland one of the second output signals.

According to another aspect of an example embodiment, there is provideda direction estimation method using an acoustic sensor, the directionestimation method including obtaining a first output signal from anon-directional acoustic sensor and a plurality of second output signalsfrom a plurality of directional acoustic sensors, comparing magnitudesbetween the second output signals and phase information between thefirst output signal and one of the second output signals, and estimatinga direction of a sound source within an error range of -5 degrees to +5degrees.

The plurality of directional acoustic sensors may include threedirectional acoustic sensors provided in a triangular shape or radialshape with respect to the non-directional acoustic sensor.

The plurality of directional acoustic sensors may include twodirectional acoustic sensors provided perpendicular to each other orfour directional acoustic sensors, each two of which are provided toface each other.

The direction of the sound source may be estimated based on phaseinformation of an output signal obtained by adding the first outputsignal and the other second output signals by excluding a second outputsignal having a smallest magnitude from among the second output signals.

When the other second output signals are plural, a second output signalhaving a greatest magnitude is selected, and the direction of the soundsource may be estimated based on phase information of the output signalobtained by adding the first output signal and the selected secondoutput signal.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects, features, and advantages of exampleembodiments of the disclosure will be more apparent from the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 illustrates an example of a directional acoustic sensor;

FIG. 2 is a cross-sectional view of a resonator illustrated in FIG. 1 ;

FIG. 3 is a diagram illustrating a method of adjusting directivity byusing a plurality of acoustic sensors according to a related example.

FIG. 4 is a block diagram of a direction estimating apparatus accordingto an example embodiment;

FIG. 5 is a diagram illustrating a directional acoustic sensor accordingto an embodiment and a directional pattern of the directional acousticsensor;

FIG. 6 is a diagram illustrating results of measurement of frequencyresponse characteristics of the directional acoustic sensor;

FIG. 7 is a diagram illustrating results of measurement of a directionalpattern of the directional acoustic sensor;

FIGS. 8A and 8B are diagrams illustrating signal processing of anacoustic sensor according to an example embodiment;

FIGS. 9A and 9B are graphs showing a result of sensing, by acousticsensors, sound transmitted from a front direction, and sound transmittedfrom a rear side direction, according to an example embodiment;

FIGS. 10A, 10B, 10C, and 10D are diagrams illustrating examples of thenumber and arrangement of a non-directional acoustic sensor and aplurality of directional acoustic sensors, according to an exampleembodiment;

FIGS. 11 and 12 are diagrams illustrating power of each directionalacoustic sensor according to an angle and ratios between powers ofrespective directional acoustic sensors, in the arrangement illustratedin FIG. 10A;

FIGS. 13, 14, and 15 are flowcharts illustrating distinguishing of anangle in a direction estimation algorithm according to various exampleembodiments;

FIG. 16 is a diagram illustrating a result of direction estimationaccording to an example embodiment;

FIG. 17 is a block diagram illustrating a schematic structure of anelectronic device including a direction estimating apparatus accordingto another example embodiment; and

FIGS. 18, 19, 20, and 21 are example diagrams illustrating applicationsof various electronic devices to which the direction estimatingapparatus according to another example embodiment may be applied.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of whichare illustrated in the accompanying drawings, wherein like referencenumerals refer to like elements throughout. In this regard, the exampleembodiments may have different forms and should not be construed asbeing limited to the descriptions set forth herein. Accordingly, theembodiments are merely described below, by referring to the figures, toexplain aspects. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items. Expressionssuch as “at least one of,” when preceding a list of elements, modify theentire list of elements and do not modify the individual elements of thelist. For example, the expression, “at least one of a, b, and c,” shouldbe understood as including only a, only b, only c, both a and b, both aand c, both b and c, or all of a, b, and c.

The terms used in the example embodiments below are those general termscurrently widely used in the art in consideration of functions in regardto the present embodiments, but the terms may vary according to theintention of those of ordinary skill in the art, precedents, or newtechnology in the art. Also, specified terms may be selectedarbitrarily, and in this case, the detailed meaning thereof will bedescribed in the detailed description of the relevant exampleembodiment. Thus, the terms used in the example embodiments should beunderstood not as simple names but based on the meaning of the terms andthe overall description of the embodiments.

It will also be understood that when an element is referred to as being“on” or “above” another element, the element may be in direct contactwith the other element or other intervening elements may be present. Thesingular forms include the plural forms unless the context clearlyindicates otherwise.

In the description of the embodiments, when a portion “connects” or is“connected” to another portion, the portion contacts or is connected tothe other portion not only directly but also electrically through atleast one of other portions interposed therebetween.

Herein, the terms such as “comprise” or “include” should not beconstrued as necessarily including various elements or processesdescribed in the specification, and it should be construed that some ofthe elements or the processes may not be included, or additionalelements or processes may be further included.

In the present description, terms including ordinal numbers such as“first″”, “second”, etc. are used to describe various elements but theelements should not be defined by these terms. The terms are used onlyfor distinguishing one element from another element.

In the example embodiments, an acoustic sensor may be a microphone, andrefer to an apparatus receiving a sound wave, which is a wave in air,and converting the same to an electrical signal.

In the example embodiments, an acoustic sensor assembly is used to referto an acoustic sensor or a microphone and a processor for controllingthe acoustic sensor or the microphone, and calculating necessaryfunctions. In addition, the acoustic sensor assembly may refer to anapparatus configured to estimate a direction by using the acousticsensor according to an example embodiment.

The example embodiments relate to an acoustic sensor assembly, anddetailed descriptions of matters widely known to those of ordinary skillin the art to which the following example embodiments belong areomitted.

Description of the following example embodiments should not be construedas limiting or defining the scope of the present disclosure, and detailsthat are easily derivable by one of ordinary skill in the art to whichthe present disclosure pertains are construed as being in the scope ofthe embodiments. Hereinafter, example embodiments that are just forillustration are described in detail with reference to the attacheddrawings.

FIG. 1 illustrates an example of a directional acoustic sensor 10. FIG.2 is a cross-sectional view of a resonator 102 illustrated in FIG. 1 .

Referring to FIGS. 1 and 2 , the directional acoustic sensor 10 mayinclude a support 101 and a plurality of resonators 102. A cavity 105may be formed in the support 101 to pass through the support 101. As thesupport 101, for example, a silicon substrate, may be used, but is notlimited thereto.

The plurality of resonators 102 may be arranged in the cavity 105 of thesupport 101 in a certain form. The resonators 102 may be arrangedtwo-dimensionally without overlapping each other. As illustrated in FIG.2 , an end of each of the resonators 102 may be fixed to the support101, and the other end thereof may extend toward the cavity 105. Each ofthe resonators 102 may include a driving unit 108 moving by reacting toinput sound and a sensing unit 107 sensing a movement of the drivingunit 108. The resonators 102 may also include a mass body 109, forproviding a certain mass to the driving unit 108, that is provided, forexample, at one end of the resonator opposite to the support 101.

The resonators 102 may be provided to sense, for example, acousticfrequencies of different bands. For example, the resonators 102 may beprovided to have different center frequencies or resonance frequencies.To this end, the resonators 102 may be provided to have differentdimensions from each other. For example, the resonators 102 may beprovided to have different lengths, widths or thicknesses from eachother.

Dimensions, such as widths or thicknesses of the resonators 102, may beset by considering a desired resonance frequency with respect to theresonators 102. For example, the resonators 102 may have dimensions,such as a width from about several µm to several hundreds of µm, athickness of several µm or less, and a length of about several mm orless. The resonators 102 having fine sizes may be manufactured by amicro electro mechanical system (MEMS) process.

FIG. 3 is a diagram illustrating a method of adjusting directivity byusing a plurality of acoustic sensors, according to a related example.Referring to FIG. 3 , in a method of adjusting directivity by using aplurality of acoustic sensors 31, the plurality of acoustic sensors 31may be used to hear sound in a particular direction louder than sound inother directions. The plurality of acoustic sensors 31 may be arrangedspaced apart at a certain distance D, a time or phase delay that soundreaches each acoustic sensor 31 is caused due to the distance D, and theoverall directivity may be adjusted by varying the degrees ofcompensation for the time delay or phase delay. The above method ofadjusting directivity may be referred to as time difference of arrival(TDOA). However, the above method is based on the assumption that thereis a difference in times that sound reaches each acoustic sensor.Therefore, there may be a restriction in setting a distance betweenacoustic sensors as the distance needs to be set by considering awavelength of an audible frequency band. The restriction in setting adistance between acoustic sensors may also limit providing a compactsize of a device performing the above method. In particular, as a lowfrequency has a longer wavelength, to distinguish a sound of a lowfrequency, a distance between acoustic sensors needs to be relativelybroad and a signal-to-noise ratio (SNR) of each acoustic sensor needs tobe relatively high.

Moreover, as phases differ according to frequency bands of sound sensedby each acoustic sensor in the TDOA, the phases may have to becompensated for with respect to each frequency band. In order tocompensate for the phase of each frequency, a complex signal processingprocess of applying an appropriate weight to each frequency may benecessary in the method described above.

In addition, to estimate a direction of a sound source by using TDOA, asignal in an array of a plurality of non-directional microphones isfrequently used. A time delay between signals obtained by eachmicrophone may be calculated, and a direction from which a sound sourcecame is estimated based on the time delay. However, the accuracy of thedirection estimation is dependent on the size of the array (distancebetween the microphones) and the time delay.

Another method is to estimate a direction of a sound source based on theintensity difference. This method uses a difference between intensitiesor levels measured by each microphone to estimate a direction. Fromwhich direction a sound source came is determined based on the magnitudeof a signal measured in a time domain. As a size difference between eachmicrophone is used, gain calibration is to be done very accurately, anda large number of microphones are required to improve performance.

When using the TDOA-based direction estimation method, the principle ofgenerating a difference in phases between the microphones for eachfrequency of a sound source according to the size of the microphonearray is utilized. Therefore, the size of the array and a wavelength ofa sound source to be estimated have a physical relationship, and thesize of the array determines the direction estimation performance.

A method of utilizing a time difference or intensity difference betweenmicrophones, according to related art, requires a large number ofmicrophones by increasing a size of the array in order to improve thedirection estimation performance. In addition, in the timedifference-based estimation method, a digital signal processing deviceis required to calculate different time delays and phase differences foreach frequency, and the performance of the device is a factor limitingthe direction estimation performance.

A direction estimating apparatus using an acoustic sensor, according toan example embodiment, provides a direction estimation algorithm using adirectional/non-directional microphone array. By using a channel moduleincluding one non-directional microphone and two or more directionalmicrophones, a direction of a sound source coming from 360 degreesomni-directionally is detected. In an example embodiment, by utilizingthe fact that a directional shape of a directional microphone isfigure-of-8, regardless of frequency, a direction of a sound source isestimated based on power of the sound source. Therefore, the directionof the sound source may be estimated by using an array having a smallsize, for example, an array within 3 cm, and with high accuracy, andvoice separation based on spatial information may also be performed.

Hereinafter, an efficient structure and operation of a directionestimating apparatus according to the present disclosure are describedin detail with reference to the drawings.

FIG. 4 is a block diagram of a direction estimating apparatus includingan acoustic sensor, according to an example embodiment. Referring toFIG. 4 , a direction estimating apparatus 4 may include a processor 41,a non-directional acoustic sensor 42, and a plurality of directionalacoustic sensors 43 a, 43 b,..., 43 n. The direction estimatingapparatus 4 may obtain sound around the direction estimating apparatus 4by using the processor 41, the non-directional acoustic sensor 42, andthe plurality of directional acoustic sensors 43 a, 43 b, ..., 43 n.

The non-directional acoustic sensor 42 may sense sound in all directionssurrounding the non-directional acoustic sensor 42. The non-directionalacoustic sensor 42 may have directivity for uniformly sensing sound inall directions. For example, the directivity for uniformly sensing soundin all directions may be omni-directional or non-directional.

The sound sensed using the non-directional acoustic sensor 42 may beoutput as a same output signal from the non-directional acoustic sensor42, regardless of a direction in which the sound is input. Accordingly,a sound source reproduced based on the output signal of thenon-directional acoustic sensor 42 may not include information ondirections.

A directivity of an acoustic sensor may be expressed using a directionalpattern, and the directional pattern may refer to a pattern indicating adirection in which an acoustic sensor may receive a sound source.

A directional pattern may be illustrated to identify sensitivity of anacoustic sensor according to a direction in which sound is transmittedbased on a 360° space surrounding the acoustic sensor having thedirectional pattern. For example, a directional pattern of thenon-directional acoustic sensor 42 may be illustrated in a circle toindicate that the non-directional acoustic sensor 42 has the samesensitivity to sounds transmitted 360° non-directionally. A specificapplication of the directional pattern of the non-directional acousticsensor 42 will be described later with reference to FIGS. 8A and 8B.

Each of the plurality of directional acoustic sensors 43 a, 43 b,..., 43n may have a same configuration as the directional acoustic sensor 10illustrated in FIG. 1 described above. The plurality of directionalacoustic sensors 43 a, 43 b,..., 43 n may sense sound from a front side(e.g., +z direction in FIG. 1 ) and a rear side (e.g., -z direction ofFIG. 1 ). Each of the plurality of directional acoustic sensors 43 a, 43b,..., 43 n may have directivity of sensing sounds from the front sideand the rear side. For example, directivity for sensing sounds from afront side direction and a rear side direction may be bi-directional.

The plurality of directional acoustic sensors 43 a, 43 b,..., 43 n maybe arranged adjacent to and to surround the non-directional acousticsensor 42. The number and arrangement of the plurality of directionalacoustic sensors 43 a, 43 b,..., 43 n will be described later in detailwith reference to FIGS. 10A to 10D.

The processor 41 controls the overall operation of the directionestimating apparatus 4 and performs signal processing. The processor 41may select at least one of output signals of acoustic sensors havingdifferent directivities, thereby calculating an acoustic signal having asame directivity as those of the non-directional acoustic sensor 42 andthe plurality of directional acoustic sensors 43 a, 43 b, ..., 43 n. Anacoustic signal having a directional pattern of an acoustic sensorcorresponding to an output signal selected by the processor 41 may becalculated based on the output signal selected by the processor 41. Forexample, the selected output signal may be identical to the acousticsignal. The processor 41 may adjust directivity by selecting adirectional pattern of the direction estimating apparatus 4 as adirectional pattern of an acoustic sensor corresponding to the selectedoutput signal, and may reduce or loudly sense sound transmitted in acertain direction according to situations.

An acoustic signal refers to a signal including information aboutdirectivity, like output signals of the non-directional acoustic sensor42 and the plurality of directional acoustic sensors 43 a, 43 b, ..., 43n, and some of the output signals may be selected and determined asacoustic signals or may be newly calculated based on calculation of someof the output signals. A directional pattern of an acoustic signal maybe in a same shape as directional patterns of the non-directionalacoustic sensor 42 and the plurality of directional acoustic sensors 43a, 43 b, ..., 43 n or in a different shape, and have a same or differentdirectivity. For example, there may be no limitation on a directionalpattern or directivity of an acoustic signal.

The processor 41 may obtain output signals of the non-directionalacoustic sensor 42 and/or the plurality of directional acoustic sensors43 a, 43 b,..., 43 n, and may calculate an acoustic signal having adifferent directivity from those of the non-directional acoustic sensor42 and the plurality of directional acoustic sensors 43 a, 43 b, ..., 43n included in the direction estimating apparatus 4 by selectivelycombining the obtained output signals. For example, the processor 41 maycalculate an acoustic signal having a different directional pattern fromdirectional patterns of the non-directional acoustic sensor 42 and theplurality of directional acoustic sensors 43 a, 43 b, ..., 43 n. Theprocessor 41 may calculate an acoustic signal having a directionalpattern oriented toward a front of a directional acoustic sensor (e.g.,43 a), depending on the situation.

The processor 41 may calculate an acoustic signal by calculating atleast one of a sum of and a difference between certain ratios of anoutput signal of the non-directional acoustic sensor 42 and outputsignals of the plurality of directional acoustic sensors 43 a, 43 b,..., 43 n.

The processor 41 may obtain sound around the direction estimatingapparatus 4 by using an acoustic signal. The processor 41 may obtainambient sound by distinguishing a direction of a sound transmitted tothe direction estimating apparatus 4 by using an acoustic signal. Forexample, when the processor 41 records a sound source transmitted fromthe right side of the direction estimating apparatus 4 and provides therecorded sound source to a user, the user may hear the sound source asif the sound source is coming from the right side of the user. When theprocessor 41 records a sound source circling the direction estimatingapparatus 4 and provides the recorded sound source to the user, the usermay hear the sound source as if the sound source is circling the user.

The processor 41 may obtain a first output signal from thenon-directional acoustic sensor 42 and a plurality of second outputsignals from the plurality of directional acoustic sensors 43 a, 43b,... 43 n, and estimate a direction of a sound source within an errorrange from -5 degrees to +5 degrees by comparing magnitudes between thesecond output signals and phase information between the first outputsignal and one of the second output signals.

The processor 41 may exclude a second output signal having the smallestmagnitude among the second output signals. The processor 41 may sum upthe first output signal and the remaining second output signals otherthan the second output signal having the smallest magnitude, andestimate a direction of a sound source by using phase information of thesummed output signals. Here, when the remaining second output signalsare plural, the processor 41 may select a second output signal having agreatest magnitude. In addition, the processor 41 may estimate adirection of a sound source by using phase information of an outputsignal obtained by summing up and adding the first output signal and thesecond output signal having a greatest magnitude.

The processor 41 may estimate a direction of a sound source by usingvarious algorithms according to the number and arrangement ofdirectional acoustic sensors. The method is in further detail later withreference to FIGS. 13 and 15 .

The processor 41 may include a single processor core (single-core) or aplurality of processor cores (multi-core). The processor 41 may processor execute programs and/or data stored in a memory. In some exampleembodiments, the processor 41 may control a function of the directionestimating apparatus 4 by executing programs stored in a memory. Theprocessor 41 may be implemented as a central processing unit (CPU), agraphics processing unit (GPU), an application processor (AP), or thelike.

FIG. 5 is a diagram illustrating a directional acoustic sensor accordingto an example embodiment and a directional pattern of the directionalacoustic sensor. Referring to FIG. 5 , a directional acoustic sensor 10may include bi-directional patterns 51 and 52. For example, thebi-directional patterns 51 and 52 may include figure-8 type directionalpatterns including a front side portion 51 oriented toward a front sideof the directional acoustic sensor 10 (+z direction) and a rear sideportion 52 oriented toward a rear side of the directional acousticsensor 10 (-z direction).

FIG. 6 is a diagram illustrating results of measurement of frequencyresponse characteristics of the directional acoustic sensor 10.Referring to FIG. 6 , the directional acoustic sensor 10 has uniformsensitivity with respect to various frequencies. In a frequency rangefrom 0 Hz to 8000 Hz, sensitivity marked by a dashed line is uniformlyat -40 dB, and noise marked by a solid line is at -80 dB. Thedirectional acoustic sensor 10 has uniform sensitivity with respect tovarious frequencies, and may thus uniformly sense sounds of the variousfrequencies.

FIG. 7 is a diagram illustrating results of measurement of a directionalpattern of the directional acoustic sensor 10. As illustrated in FIG. 7, the directional acoustic sensor 10 has a uniform, bi-directionalpattern with respect to various frequencies. For example, thedirectional acoustic sensor 10 has directivity in a +z axis directionand a -z axis direction of FIG. 1 , which are a 0-degree direction and a180-degree direction, respectively.

FIG. 8A is a diagram illustrating signal processing of a directionestimating apparatus according to an example embodiment. Referring toFIG. 8A, the processor 41 may calculate an acoustic signal bycalculating at least one of a sum of and a difference between certainratios of an output signal of the non-directional acoustic sensor 42 andan output signal of the directional acoustic sensor 10. An acousticsignal may include a digital signal calculated based on output signalsso that the acoustic signal has a different shape or a differentdirectivity from those of direction patterns (a bi-directional pattern81 and an omni-directional pattern 82) of the directional acousticsensor 10 and the non-directional acoustic sensor 42. For example, in acalculation to calculate an acoustic signal, when an output signal ofthe non-directional acoustic sensor 42 is G1, an output signal of thedirectional acoustic sensor 10 is G2, and a ratio of the output signalG2 of the directional acoustic sensor 10 to the acoustic signal G1 ofthe non-directional acoustic sensor 42 is 1:k, a sum of certain ratiosbetween the output signals G1 and G2 may be calculated using a formulaof G1+kG2, and a difference between the certain ratios of the outputsignals G1 and G2 may be calculated using a formula of G1-kG2. A ratioof each of the output signals may be preset according to a shape ordirectivity of a required, appropriate directional pattern.

The processor 41 may calculate an acoustic signal having a directionalpattern oriented toward the front side direction of the directionalacoustic sensor 10 (e.g., +z direction of FIG. 5 ) by calculating a sumof certain ratios of an output signal of the non-directional acousticsensor 42 and an output signal of the directional acoustic sensor 10.

The non-directional acoustic sensor 42 is oriented in all directions,and thus, there may be no difference in output signals regardless of adirection in which sound is transmitted. However, for convenience ofdescription below, the front side direction of the directional acousticsensor 10 will be assumed to be identical to a front side direction ofthe non-directional acoustic sensor 42.

For example, the processor 41 may calculate an acoustic signal having auni-directional pattern 83 by calculating a sum of 1:1 ratios of anoutput signal of the non-directional acoustic sensor 42 and an outputsignal of the directional acoustic sensor 10. The uni-directionalpattern 83 may have a directivity facing the front of the directionalacoustic sensor 10. However, the uni-directional pattern 83 may includea directional pattern covering a broader range to the left and theright, compared to a front portion of the bi-directional pattern 81. Forexample, the uni-directional pattern 83 may include a cardioiddirectional pattern.

The directional acoustic sensor 10 may include the bi-directionalpattern 81, and the non-directional acoustic sensor 42 may include theomni-directional pattern 82. The directional acoustic sensor 10 maysense a sound that is in-phase with a phase of a sound sensed by thenon-directional acoustic sensor 42 from a front side direction of thebi-directional pattern 81 (e.g., +z direction of FIG. 5 ), and a soundthat is anti-phase with a phase of a sound sensed by the non-directionalacoustic sensor 42 from a rear side direction of the bi-directionalpattern 81 (e.g., -z direction of FIG. 5 ).

FIG. 9A is a graph showing a result of sensing sound transmitted from afront direction, by acoustic sensors, according to an exampleembodiment. FIG. 9B is a graph showing a result of sensing soundtransmitted from a rear side direction, by acoustic sensors, accordingto an example embodiment.

Referring to FIGS. 9A and 9B, a sound transmitted from the front sidedirection of the directional acoustic sensor 10 and sound transmittedfrom the front side direction of the non-directional acoustic sensor 42are in-phase with each other, and the sound transmitted from the frontdirection of the directional acoustic sensor 10 and sound transmittedfrom the rear side direction of the non-directional acoustic sensor 42have a phase difference of 180° from each other such that peaks andtroughs alternately cross each other.

Referring back to FIG. 8A, sounds transmitted from the front sidedirection are in-phase with each other, and sounds transmitted from therear side direction are in anti-phase with each other, and thus, some ofthe output signals are added and some others are offset and an acousticsignal having the uni-directional pattern 83 oriented in the frontdirection may be calculated, accordingly.

FIG. 8B is a diagram illustrating signal processing of a directionestimating apparatus according to an example embodiment. Referring toFIG. 8B, the processor 41 may calculate an acoustic signal having adirectional pattern oriented toward the rear side direction of thedirectional acoustic sensor 10 (e.g., -z direction of FIG. 5 ) bycalculating a difference between certain ratios of an output signal ofthe non-directional acoustic sensor 42 and an output signal of thedirectional acoustic sensor 10.

For example, the processor 41 may calculate an acoustic signal having auni-directional pattern 84 by calculating a difference between 1:1ratios of an output signal of the non-directional acoustic sensor 42 andan output signal of the directional acoustic sensor 10. Opposite to theuni-directional pattern 83 of FIG. 8A, the uni-directional pattern 84may have a directivity facing a rear surface of the directional acousticsensor 10. The uni-directional pattern 84 may include a directionalpattern covering a broader range to the left and the right, compared toa rear side portion of the bi-directional pattern 81. For example, theuni-directional pattern 83 may include a cardioid directional pattern.

While a method of calculating an acoustic signal having auni-directional pattern by calculating a sum of or a difference betweenan output of the directional acoustic sensor 10 and an output of thenon-directional acoustic sensor 42 is described above, this is merely anexample, and the control of directivity is not limited to the methoddescribed above.

The processor 41 may calculate an acoustic signal having a newbi-directional pattern differing from bi-directivity of respectivedirectional acoustic sensors by selecting only a non-directionalpattern, or selecting only a bi-directional pattern of a directionalacoustic sensor oriented toward a certain direction, or calculatingoutput signals of directional acoustic sensors, according to situations.

FIGS. 10A to 10D are diagrams illustrating examples of the number andarrangement of a non-directional acoustic sensor and a plurality ofdirectional acoustic sensors, according to an example embodiment.

Referring to FIG. 10A, in an example, the non-directional acousticsensor 42 is arranged in a center, and three directional acousticsensors 10 a, 10 b, and 10 c are arranged at a distance of 120 degrees.The above shape may be a triangular arrangement, and the overall sizemay be within 3 cm.

Referring to FIG. 10B, in another example, the non-directional acousticsensor 42 may be arranged in a center, and the three directionalacoustic sensors 10 a, 10 b, and 10 c may be arranged at a distance of120 degrees, and the above form may be in a radial arrangement. LikeFIG. 10A, the overall size may be within 3 cm.

Here, the directional acoustic sensors have a directional pattern in theform of a figure-of-8. The directional pattern has a cosine functionvalue according to an angle. Therefore, outside a +/- 60 degree range,power detected by the directional acoustic sensors is reduced to half ormore than half. Therefore, considering the above-described reason andthe cost incurred by the increase in the number of sensors, using threedirectional acoustic sensors may be more efficient.

According to an example embodiment, directional acoustic sensors may bearranged in a triangular shape illustrated in FIG. 10A or a radial shapeillustrated in FIG. 10B. When the directional acoustic sensors 10 a, 10b, and 10 c illustrated in FIGS. 10A and 10B are referred to as channel1 (ch. 1), channel 2 (ch. 2), and channel 3 (ch. 3), respectively, idealpower of each channel according to an angle is as illustrated in FIG. 11. In addition, ratios between the powers of the channels according to anangle are obtained as illustrated in FIG. 12 . Here, a ratio between twolargest channels among the three channels is illustrated by a dashedline 1200. In an example embodiment, a power ratio of two channels maybe used for direction estimation except for a channel having lowestpower from among the three channels.

Referring to FIG. 13 , as illustrated in FIGS. 10A and 10B, a directionestimation algorithm for a 4-channel acoustic sensor arrangement isdescribed.

First, a channel having a minimum output among the channels of the threedirectional acoustic sensors is determined. Next, a channel having asmallest output from among the remaining two channels is determined.Then, a phase between the directional acoustic sensor and thenon-directional acoustic sensor is checked.

When the power or magnitude of channel 1 (ch. 1) among the threechannels is the smallest, the larger channel among the remaining twochannels, that is, channel 2 and channel 3, is determined.

When channel 2 (ch. 2) is larger, it is determined whether a phase of anoutput signal obtained by summing up and adding an output signal ofchannel 2 (ch. 2) and an output signal of the non-directional acousticsensor 42 is greater than 0. When the phase of the obtained outputsignal is greater than 0, a direction of the sound source may beestimated to be between 90 degrees and 120 degrees, and otherwise, thedirection of the sound source may be estimated to be between 270 degreesand 300 degrees, which is inverted by 180 degrees.

Conversely, when channel 3 (ch. 3) is larger, it is determined whether aphase of an output signal obtained by adding an output signal of thechannel 3 (ch. 3) and an output signal of the non-directional acousticsensor 42 is greater than 0. When the phase of the obtained outputsignal is greater than 0, a direction of the sound source may beestimated to be between 240 degrees and 270 degrees, and otherwise, thedirection of the sound source may be estimated to be between 60 degreesand 90 degrees, which is inverted by 180 degrees.

Similarly, when the power or magnitude of channel 2 (ch.2) among thethree channels is the smallest or when the power or magnitude of channel3 (ch.3) is the smallest among the three channels, a direction of asound source may be estimated in a similar manner to the methoddescribed above.

After a domain for an angle range is determined using the above method,a direction or angle of the sound source may be calculated according toEquation 1 below.

$\theta = {\sum\limits_{i = 0}^{3}{c_{i} \cdot r^{i}}}\left( {c_{1} = coefficient,\mspace{6mu} r_{i} = power\mspace{6mu} ratio} \right)$

In an example embodiment, in direction estimation using a 4-channelacoustic sensor array (one non-directional acoustic sensor and threedirectional acoustic sensors), by excluding a channel having a smallestpower for each angle, from angle calculation when estimating adirection, an error due to a reflected wave due to a reduction in sizerejection of a directional microphone in a general noise environment maybe minimized.

Tests were conducted while changing a direction of a sound source in ageneral noise environment by using the direction estimation methodaccording to the example embodiment, and as a result, as illustrated inFIG. 16 , a direction may be estimated within an error range of +/- 5degrees by using a 4-channel microphone array having a diameter of 3 cmor less.

Referring to back FIG. 10C, in an example, the non-directional acousticsensor 42 is arranged in a center, and two directional acoustic sensors10 a and 10 b are arranged to be perpendicular to each other. As the twodirectional acoustic sensors are arranged perpendicular to each other,an angle for estimating a direction may be calculated based on atrigonometric function. A direction estimation algorithm of a 3-channelarray is described with reference to FIG. 14 .

Referring to FIG. 14 , a larger channel is determined by comparingpowers of two directional acoustic sensors. A phase between the twodirectional acoustic sensor and the non-directional acoustic sensor ischecked.

When a first channel (ch.1) among the two channels is larger, whether aphase of an output signal obtained by adding an output signal of thefirst channel and an output signal of the non-directional acousticsensor is greater than 0 is compared. When the phase of the obtainedoutput signal is greater than 0, whether a phase of an output signalobtained by adding an output signal of a second channel (ch.2) and anoutput signal of the non-directional acoustic sensor is greater than 0is compared. When the phase of the obtained output signal is greaterthan 0, a direction of the sound source may be estimated to be between 0degrees and 45 degrees, and otherwise, the direction of the sound sourcemay be estimated to be between 315 degrees and 360 degrees.

When the phase of the output signal obtained by adding the output signalof the first channel (ch.1) and the output signal of the non-directionalacoustic sensor is less than 0, in the same manner, whether an outputsignal obtained by adding the output signal of the second channel (ch.2)and the output signal of the non-directional acoustic sensor is greaterthan 0 is compared. When the phase of the obtained output signal isgreater than 0, a direction of the sound source may be estimated to bebetween 135 degrees and 180 degrees, and otherwise, the direction of thesound source may be estimated to be between 180 degrees and 225 degrees.

Similarly, when the second channel (ch.2) is greater among the twochannels, a direction of a sound source may be estimated.

After a domain of a direction is determined according to the methoddescribed above, an angle or direction may be calculated according toEquation 2.

$\begin{array}{l}{\theta = cos^{- 1}\frac{P_{1}}{\sqrt{\left( P_{1} \right)^{2} + \left( P_{2} \right)^{2}}}} \\\left( {P_{1} = max\mspace{6mu} ch.\mspace{6mu} power,\mspace{6mu} P_{2} = min\mspace{6mu} ch.\mspace{6mu} power} \right)\end{array}$

Referring to back FIG. 10D, in an example, the non-directional acousticsensor 42 is arranged in a center, and four directional acoustic sensors10 a, 10 b, 10 c, and 10 d are arranged. The directional acousticsensors 10 a to 10 d are arranged to face each other. In the abovearrangement, there are channels facing each other (ch.1 & ch.3, and ch.2& ch.4). Here, the channels facing each other have opposite phases.However, when there is an obstacle in an opposite direction, theresponse magnitude of a directional microphone is slightly reduced, andat -45 degrees to 45 degrees, channel 1 (ch. 1) is larger than channel 3(ch. 3), and at 135 degrees to 225 degrees, channel 3 (ch.3) is largerthan channel 1 (ch.1). A 5-channel direction estimation algorithm usingthese characteristics is described with reference to FIG. 15 .

Referring to FIG. 15 , a channel having smallest power among fourchannels is determined. Then, the power of the channel having greatestpower and powers of two adjacent channels thereto are compared.

When power of channel 1 (ch.1) is greatest among the four channels,powers of adjacent channels, channel 2 (ch.2) and channel 4 (ch. 4), arecompared. When the power of channel 2 (ch. 2) is greater, a direction ofa sound source may be estimated to be between 0 degrees and 45 degrees,otherwise, the direction of the sound source may be estimated to bebetween 315 degrees and 360 degrees.

When power of channel 2 (ch.2) is greatest among the four channels,powers of adjacent channels, channel 1 (ch.1) and channel 3 (ch. 3) arecompared. When the power of channel 1 (ch. 1) is greater, a direction ofa sound source may be estimated to be between 45 degrees and 90 degrees,otherwise, the direction of the sound source may be estimated to bebetween 90 degrees and 135 degrees.

Similarly, a direction of a sound source may be estimated also when thepower of channel 3 (ch. 3) or channel 4 (ch. 4) is greatest.

After a domain of a direction is determined according to the methoddescribed above, an angle or direction may be calculated according toEquation 2 above.

While an arrangement including one non-directional acoustic sensor andtwo to four directional acoustic sensors is described with reference toFIGS. 10A to 10D, embodiments are not limited thereto, and five or moreacoustic sensors may be arranged in various shapes or polygonal shapes.Also, in this case, an algorithm for estimating a direction of a soundsource may be variously changed according to the number and arrangementof directional acoustic sensors. For example, a direction of a soundsource may be estimated according to the geometric relationship of thedirectional acoustic sensors in various arrangements.

FIG. 17 is a block diagram illustrating a schematic structure of anelectronic device including a direction estimating apparatus accordingto another example embodiment.

The direction estimating apparatus described above may be used invarious electronic devices. The electronic devices may include, forexample, a smartphone, a portable phone, a mobile phone, a personaldigital assistant (PDA), a laptop, a personal computer (PC), variousportable devices, home appliances, security cameras, medical cameras,automobiles, and Internet of Things (IoT) devices, and other mobile ornon-mobile computing devices, and are not limited thereto.

The electronic devices may further include an AP, and may control aplurality of hardware or software components by driving an operatingsystem or an application program through the processor, and may performvarious data processing and computations. The processor may furtherinclude a GPU and/or an image signal processor.

Referring to FIG. 17 , in a network environment ED00, an electronicdevice ED01 may communicate with another electronic device ED02 througha first network ED99 (e.g., a short-range wireless communicationnetwork) or may communicate with another electronic device ED04 and/or aserver ED08 through a second network ED99 (e.g., a remote wirelesscommunication network, etc.). The electronic device ED01 may communicatewith the electronic device ED04 through the server ED08. The electronicdevice ED01 may include a processor ED20, a memory ED30, an input deviceED50, a sound output device ED55, a display device ED60, an audio moduleED70, a sensor module ED76, and an interface ED77, a haptic module ED79,a camera module ED80, a power management module ED88, a battery ED89, acommunication module ED90, a subscriber identification module ED96,and/or an antenna module ED97. Some of these components (e.g., thedisplay device ED60) may be omitted from the electronic device ED01 orother components may be added to the electronic device ED01. Some ofthese components may be implemented as a single integrated circuit. Forexample, the sensor module ED76 (fingerprint sensor, iris sensor,illuminance sensor, etc.) may be embedded in the display device ED60(display, etc.).

By executing software (e.g., a program ED40), the processor ED20 maycontrol one or a plurality of other components (hardware, softwarecomponents, etc.) of the electronic device ED01 connected to theprocessor ED20 and may perform various data processing or computations.As part of data processing or computations, the processor ED20 may loadcommands and/or data received from other components (the sensor moduleED76, the communication module ED90, etc.), into a volatile memory ED32,process the commands and/or data stored in the volatile memory ED32, andstore resultant data in a nonvolatile memory ED34. The processor ED20may include a main processor ED21 (a CPU, an AP, etc.) and an auxiliaryprocessor ED23 (GPU, an image signal processor, a sensor hub processor,a communication processor, etc.) that may be operated independently ofor together with the main processor ED21. The auxiliary processor ED23may use less power than the main processor ED21 and may perform aspecialized function.

The auxiliary processor ED23 may be configured to control functionsand/or states related to some of the components of the electronic deviceED01 (the display device ED60, the sensor module ED76, the communicationmodule ED90, etc.) by replacing the main processor ED21 while the mainprocessor ED21 is in an inactive state (sleep state), or together withthe main processor ED21 when the main processor ED21 is in an activestate (application execution state). The auxiliary processor ED23 (animage signal processor, a communication processor, etc.) may beimplemented as a portion of other functionally related components (thecamera module ED80, the communication module ED90, etc.).

The memory ED30 may store a variety of data required by the componentsof the electronic device ED01 (the processor ED20, the sensor moduleED76, etc.). The data may include, for example, input data and/or outputdata for software (e.g., the program ED40) and instructions relatedthereto. The memory ED30 may include a volatile memory ED32 and/or anonvolatile memory ED34. The nonvolatile memory ED34 may include aninternal memory ED36 fixedly mounted in the electronic device ED01 and aremovable external memory ED38.

The program ED40 may be stored as software in the memory ED30, and mayinclude an operating system ED42, middleware ED44, and/or an applicationED46.

The input device ED50 may receive a command and/or data to be used in acomponent of the electronic device ED01 (e.g., the processor ED20) fromthe outside of the electronic device ED01 (a user, etc.). The inputdevice ED50 may include a microphone, a mouse, a keyboard, and/or adigital pen (e.g., a stylus pen).

The sound output device ED55 may output a sound signal to the outside ofthe electronic device ED01. The sound output device ED55 may include aspeaker and/or a receiver. The speaker may be used for general purposes,such as multimedia playback or recording playback, and the receiver maybe used to receive incoming calls. The receiver may be integrated as aportion of the speaker or may be implemented as an independent separatedevice.

The display device ED60 may visually provide information to the outsideof the electronic device ED01. The display device ED60 may include adisplay, a hologram device, or a projector and a control circuit forcontrolling these devices. The display device ED60 may include touchcircuitry configured to sense a touch, and/or sensor circuitryconfigured to measure intensity of a force generated by the touch (e.g.,a pressure sensor).

The audio module ED70 may convert sound into an electrical signal, orconversely, convert an electrical signal into sound. The audio moduleED70 may obtain sound through the input device ED50 or output soundthrough a speaker and/or a headphone of other electronic devices (theelectronic device ED02, etc.) directly or wirelessly connected to thesound output device ED55 and/or the electronic device ED01. The audiomodule ED70 may include the direction estimating apparatus according toan embodiment.

The sensor module ED76 may detect an operating state of the electronicdevice ED01 (power, temperature, etc.), or an external environmentalstate (user status, etc.), and generate an electrical signal and/or datacorresponding to the sensed state value. The sensor module ED76 mayinclude a gesture sensor, a gyro sensor, a barometric pressure sensor, amagnetic sensor, an acceleration sensor, a grip sensor, a proximitysensor, a color sensor, an infrared (IR) sensor, a biometric sensor, atemperature sensor, a humidity sensor, and/or an illuminance sensor.

The interface ED77 may support one or a plurality of designatedprotocols that may be used to directly or wirelessly connect theelectronic device ED01 to another electronic device (e.g., theelectronic device ED02). The interface ED77 may include a HighDefinition Multimedia Interface (HDMI), a Universal Serial Bus (USB)interface, a Secure Digital (SD) card interface, and/or an audiointerface.

A connection terminal ED78 may include a connector through which theelectronic device ED01 may be physically connected to another electronicdevice (e.g., the electronic device ED02). The connection terminal ED78may include an HDMI connector, a USB connector, an SD card connector,and/or an audio connector (e.g., a headphone connector).

The haptic module ED79 may convert an electrical signal into amechanical stimulus (vibration, movement, etc.) or an electricalstimulus that the user may perceive through tactile or kinestheticsense. The haptic module ED79 may include a motor, a piezoelectricelement, and/or an electrical stimulation device.

The camera module ED80 may capture a still image or record a movingpicture. The camera module ED80 may include additional lens assemblyimage signal processors, and/or flash units. A lens assembly included inthe camera module ED80 may collect light emitted from a subject, whichis an object of image capturing.

The power management module ED88 may manage power supplied to theelectronic device ED01. The power management module ED88 may beimplemented as a portion of a power management integrated circuit(PMIC).

The battery ED89 may supply power to components of the electronic deviceED01. The battery ED89 may include a non-rechargeable primary cell, arechargeable secondary cell, and/or a fuel cell.

The communication module ED90 may support establishment of a direct(wired) communication channel and/or a wireless communication channelbetween the electronic device ED01 and other electronic devices (theelectronic device ED02, the electronic device ED04, the server ED08,etc.) and communication through the established communication channel.The communication module ED90 may include one or a plurality ofcommunication processors that operate independently of the processorED20 (e.g., an AP) and support direct communication and/or wirelesscommunication. The communication module ED90 may include a wirelesscommunication module ED92 (a cellular communication module, ashort-range wireless communication module, a global navigation satellitesystem (GNSS, etc.) communication module and/or a wired communicationmodule ED94 (a local area network (LAN) communication module, a powerline communication module, etc.). Among these communication modules, acorresponding communication module may communicate with other electronicdevices through a first network ED98 (a short-range communicationnetwork such as Bluetooth, WiFi Direct, or Infrared Data Association(IrDA)) or a second network ED99 (a telecommunication network such as acellular network, the Internet, or a computer network (LAN, WAN, etc.)).These various types of communication modules may be integrated into asingle component (a single chip, etc.) or implemented as a plurality ofcomponents (multiple chips) that are separate from each other. Thewireless communication module ED92 may confirm and authenticate theelectronic device ED01 in a communication network, such as the firstnetwork ED98 and/or the second network ED99, by using subscriberinformation (e.g., International Mobile Subscriber Identifier (IMSI))stored in the subscriber identification module ED96.

The antenna module ED97 may transmit or receive signals and/or power toor from the outside (e.g., other electronic devices). An antenna mayinclude a radiator including a conductive pattern formed on a substrate(e.g., a printed circuit board (PCB)). The antenna module ED97 mayinclude one or a plurality of antennas. When a plurality of antennas areincluded, an antenna suitable for a communication method used in acommunication network, such as the first network ED98 and/or the secondnetwork ED99, may be selected by the communication module ED90 fromamong the plurality of antennas. A signal and/or power may betransmitted or received between the communication module ED90 andanother electronic device through the selected antenna. In addition tothe antenna, other components (e.g., a radio frequency integratedcircuit (RFIC)) may be included as a portion of the antenna module ED97.

Some of the components may be connected to each other through acommunication method between peripheral devices (e.g., a bus, GeneralPurpose Input and Output (GPIO), Serial Peripheral Interface (SPI),Mobile Industry Processor Interface (MIPI)) and exchange signals (e.g.,command, data, etc.).

A command or data may be transmitted or received between the electronicdevice ED01 and the external electronic device ED04 through the serverED08 connected to the second network ED99. The other electronic devicesED02 and ED04 may be of the same type as or a different type from thatof the electronic device ED01. All or some of operations performed bythe electronic device ED01 may be executed in one or a plurality ofdevices among the other electronic devices ED02, ED04, and ED08. Forexample, when the electronic device ED01 is to perform a function orservice, instead of executing the function or service by itself, arequest for performing a portion or all of the function or service maybe made to one or a plurality of other electronic devices. One or aplurality of other electronic devices receiving the request may executean additional function or service related to the request, and transmit aresult of the execution to the electronic device ED01. To this end,cloud computing, distributed computing, and/or client-server computingtechnology may be used.

FIGS. 18 to 21 are example diagrams illustrating applications of variouselectronic devices to which the direction estimating apparatus accordingto another example embodiment may be applied.

As various electronic devices include the direction estimating apparatusaccording to an example embodiment, sound may be obtained by using acertain directional pattern with respect to a certain direction, adirection of transmitted sound may be detected, or sound around theelectronic device may be obtained with spatial awareness. For example,when a first user and a second user have a conversation by using anelectronic device as a medium, the electronic device may detect adirection in which each user is located, or sense only the voice of thefirst user by using a directional pattern oriented toward the firstuser, or sense only the voice of the second user by using a directionalpattern oriented toward the second user, or simultaneously sense thevoices of both users by distinguishing directions from which each user’svoice is heard.

A direction estimating apparatus mounted on an electronic device hasuniform sensitivity to various frequencies of sensed sound, and it maybe easier to manufacture the direction estimating apparatus having acompact size as there is no restriction on distances between respectiveacoustic sensors. Also, the degree of freedom of operation of theapparatuses is relatively high because various directional patterns maybe selected and combined according to a location of a directionestimating apparatus or the conditions of the surroundings. In addition,only simple operations such as a sum or a difference are used to controlthe direction estimating apparatus, and thus computational resources maybe used more efficiently.

The direction estimating apparatus according to the example embodimentsmay be a microphone module 1800 provided in a mobile phone or smartphoneillustrated in FIG. 18 , or a microphone module 1900 provided in a TVillustrated in FIG. 19 .

In addition, the direction estimating apparatus may be a microphonemodule 2000 provided in a robot illustrated in FIG. 20 or a microphonemodule 2100 provided over the overall length of a vehicle illustrated inFIG. 21 .

Although the direction estimating apparatus described above and anelectronic device including the same have been described with referenceto the embodiment illustrated in the drawings, this is merely anexample, and it will be understood by those of ordinary skill in the artthat various modifications and equivalent other embodiments may be made.Therefore, the disclosed example embodiments should be considered in anillustrative rather than a restrictive sense. The scope of the presentdisclosure is defined not by the detailed description of the presentdisclosure but by the appended claims, and all differences within thescope will be construed as being included in the present disclosure.

The embodiments described above can be written as computer programs andcan be implemented in general-use digital computers that execute theprograms using a computer-readable recording medium. Also, datastructures used in the example embodiments described above may bewritten to the computer-readable recording medium using various means.Examples of the computer-readable recording medium include magneticstorage media (e.g., ROM, floppy disks, hard disks, etc.), opticalrecording media (e.g., CD-ROMs, or DVDs), and storage media such ascarrier waves (e.g., transmission through the Internet).

It should be understood that example embodiments described herein shouldbe considered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each exampleembodiment should typically be considered as available for other similarfeatures or aspects in other embodiments. While example embodiments havebeen described with reference to the figures, it will be understood bythose of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeas defined by the following claims and their equivalents.

What is claimed is:
 1. A direction estimating apparatus using an acoustic sensor, the direction estimating apparatus comprising: a non-directional acoustic sensor; a plurality of directional acoustic sensors provided adjacent to the non-directional acoustic sensor; and a processor configured to: obtain a first output signal from the non-directional acoustic sensor and a plurality of second output signals from the plurality of directional acoustic sensors; and estimate a direction of a sound source within an error range from -5 degrees to +5 degrees by comparing magnitudes between the two output signals and phase information between the first output signal and one of the second output signals.
 2. The direction estimating apparatus of claim 1, wherein the plurality of directional acoustic sensors comprise three directional acoustic sensors provided in a triangular shape or radial shape with respect to the non-directional acoustic sensor.
 3. The direction estimating apparatus of claim 1, wherein the processor is further configured to: exclude a second output signal having a smallest magnitude from among the second output signals; and estimate the direction of the sound source based on phase information of an output signal obtained by adding the first output signal and the other second output signals.
 4. The direction estimating apparatus of claim 3, wherein the processor is further configured to: select a second output signal having a greatest magnitude when the other second output signals are plural; and estimate the direction of the sound source based on phase information of the output signal obtained by adding the first output signal and the selected second output signal.
 5. The direction estimating apparatus of claim 1, wherein the processor is further configured to compare whether phase information between the first output signal and one of the second output signals is greater than
 0. 6. The direction estimating apparatus of claim 1, wherein the direction of the sound source is differently estimated based on a number of the plurality of directional acoustic sensors and arrangement of the plurality of directional acoustic sensors.
 7. The direction estimating apparatus of claim 1, wherein a directional shape of the second output signals includes a figure-of-8 shape regardless of a frequency of the sound source.
 8. The direction estimating apparatus of claim 1, wherein the processor is further configured to: obtain, when the plurality of directional acoustic sensors are three, the direction of the sound source according to: $\theta = {\sum\limits_{i = 0}^{3}{c_{i} \cdot r^{i}}}\mspace{6mu},$ where Ci is an arbitrary coefficient, and ri is a power factor.
 9. The direction estimating apparatus of claim 1, wherein the processor is further configured to compare, when there are two directional acoustic sensors, whether phase information of the output signal obtained by adding a second output signal having a greater magnitude among the two second output signals and the first output signal of the non-directional acoustic sensor is greater than
 0. 10. The direction estimating apparatus of claim 9, wherein the processor is further configured to obtain the direction of the sound source according to: $\theta = cos^{- 1}\frac{P_{1}}{\sqrt{\left( P_{1} \right)^{2} + \left( P_{2} \right)^{2}}}\mspace{6mu},$ where P1 is greatest power, and P2 is smallest power.
 11. The direction estimating apparatus of claim 9, wherein the two directional acoustic sensors are provided to be perpendicular to each other.
 12. The direction estimating apparatus of claim 1, wherein the processor is further configured such that, when the plurality of directional acoustic sensors are four, each two directional acoustic sensors are provided to face each other.
 13. The direction estimating apparatus of claim 12, wherein the processor is further configured to: determine a directional acoustic sensor corresponding to a second output signal having a greatest magnitude among the plurality of second output signals; and compare a magnitude of the determined directional acoustic sensor with magnitudes of second output signals of two adjacent directional acoustic sensors provided on a left side and a right side.
 14. The direction estimating apparatus of claim 1, wherein the non-directional acoustic sensor and the plurality of directional acoustic sensors are provided within a diameter of 3 cm.
 15. An electronic device comprising; a direction estimating apparatus using an acoustic sensor comprising: a non-directional acoustic sensor; a plurality of directional acoustic sensors provided adjacent to the non-directional acoustic sensor; and a processor configured to: obtain a first output signal from the non-directional acoustic sensor and a plurality of second output signals from the plurality of directional acoustic sensors; and estimate a direction of a sound source within an error range from -5 degrees to +5 degrees by comparing magnitudes between the two output signals and phase information between the first output signal and one of the second output signals.
 16. A direction estimation method using an acoustic sensor, the direction estimation method comprising: obtaining a first output signal from a non-directional acoustic sensor and a plurality of second output signals from a plurality of directional acoustic sensors; comparing magnitudes between the second output signals and phase information between the first output signal and one of the second output signals; and estimating a direction of a sound source within an error range of -5 degrees to +5 degrees.
 17. The direction estimation method of claim 16, wherein the plurality of directional acoustic sensors comprise three directional acoustic sensors provided in a triangular shape or radial shape with respect to the non-directional acoustic sensor.
 18. The direction estimation method of claim 16, wherein the plurality of directional acoustic sensors comprise two directional acoustic sensors provided perpendicular to each other or four directional acoustic sensors, each two of which are provided to face each other.
 19. The direction estimation method of claim 17, wherein the direction of the sound source is estimated based on phase information of an output signal obtained by adding the first output signal and the other second output signals by excluding a second output signal having a smallest magnitude from among the second output signals.
 20. The direction estimation method of claim 19, wherein, when the other second output signals are plural, a second output signal having a greatest magnitude is selected, and the direction of the sound source is estimated based on phase information of the output signal obtained by adding the first output signal and the selected second output signal. 